The home of the Petalars before the Great Wind. Believed to have returned to it.
The Garden is the paradise where the Petalars, a plant-like race, lived before the Great Wind blew them far away across different parts of the world. One specific group encountered by the Thundercats in the Briar Wood were looking for the Cliff of Winds to return to their homeland.
The Great Wind that scattered the Petalar race
So far, it isn't known what created the Great Wind, natural disaster or not. The Garden's location remains unknown.
Presumably, the Petalars made it back to the Garden with the help of Lion-O and the ThunderCats by riding the wind back home.